A New View of an Old Receptor

γδ T cells represent a distinct lineage of T cells that undertake a range of specific immune functions. However, compared with their αβ T cell counterparts, the mode of antigen recognition by these T cells is still relatively poorly understood (see the Perspective by Garboczi). By resolving a 3.4 angstrom structure of the complex between a specific mouse γδ T cell receptor (TCR) and its nonclassical class I major histocompatibility complex ligand, Adams et al. have generated a new model of γδ T cell recognition, which has features of both innate immune receptor recognition and adaptive recognition through recombination of germline segments. Shin et al. arrive at similar conclusions from a survey of TCR usage at the single-cell level, which leads them to suggest that γδ T cells focus on a relatively narrow range of antigenic ligands.